The bodies of vehicles designed to transport cars or other vehicles are constructed using mechanical soldering techniques to join tubular elements.
This type of structure forming the body of automobile-transporting vehicles consists of profiled tubular elements soldered together to form a frame. The upright elements are appropriately shielded by oblique posts reinforced by the addition of transverse elements to provide the necessary mechanical rigidity and support.
The devices which support and elevate the supporting platforms are displaceable along the upright elements and vertical or oblique posts located on a straight line with or near the articulating connections to the adjacent supporting platforms.
These supporting elements generally consist of peripheral slides outside tubes with the same shaped section which are displaced along these tubular elements by means of motor elements such as a screw/translation nut device or cylinders. They are usually immobilized in a given position by means of pins. For this reason, the posts and upright elements have openings on their two opposing surfaces, that is, the right and left surfaces, to engage the blocking pins.
One example of a design of this type is found in U.S. Pat. No. 3,690,717 in the name of TAYLOR.
The construction technique used in the automobile transporter described in this patent uses tubular elements with a square section mechanically soldered to longitudinal members forming a generally frame-like flank structure connected to a base-chassis.
There are slides attached to the elevating posts which are activated to move in translation along these posts by means of cylinders articulated at the base to the lower longitudinal element on the flank structure. Each slide has an articulating element joining it to a vehicle supporting platform.
This design is not practical in use. The carriage is highly susceptible to corrosion, since the elevating devices are not protected from the elements or from bumps, giving it an unsightly appearance due to rust and the openings in the posts and their components, with the various pieces, connections, wires, supply and control cables being visible and poorly arranged.
Moreover, this type of tubular flank body remains rigid under torsion, causing the chassis to be too rigid and subject to the fissures which appear due to the weight of the load and the dynamics of displacement when the base vehicle to which the structure is attached moves and stops.
The number of connection points between the tubular flanks and the chassis is multiplied in order to divide constraint concentrations in parallel.
Furthermore, corrosion resistance is reduced due to the multiple hollow elements forming partially closed areas in the mechanically soldered tubular flank structure where damp air is easily trapped and condensed.
This tendency to corrosion is increased because it is difficult to treat the interior and exterior surfaces of the profiled tubular guide elements, as well as the interior surfaces of the slides.
Moreover, the installation procedure is doomed to remain a manual procedure, since it is difficult to automate or mass produce. A simple example of the assembly difficulties encountered concerns the slide which is displaced along the tube by the motor elements for raising or lowering the platforms. It is necessary to actually thread the slide onto the tubular element which then guides it while the slide is still free, that is, before the guide is soldered to the nearby profiled tubular elements to form a frame.
Of equal importance are the difficulties in upkeep, repair, and maintenance, since replacing or removing a slide necessitates disconnecting the tube that supports it.
Finally, these devices characteristically constitute a multitude of cross-pieces, which not only lengthens construction time, but also increases the weight and cost of the unit.
Generally speaking, with this manufacturing technique the order imposed by the successive attachment operations must be respected. It cannot be modified at all for purposes of saving construction time or for reasons associated with location or work efficiency. Under these conditions, no real improvements are possible without abandoning the manufacturing technique.
In addition, the manufacturing cycle should be adaptable to the particular chassis to be equipped, as each chassis imposes different constraints respecting size and accessibility.